The Great Salt Debate Rages On

Experts disagree on how much sodium is healthy.

Salt has a bad rap. But earlier this year it got a boost from the Institute of Medicine. Kind of. In May, the IOM released a report reaffirming the long-held belief that too much salt may increase your risk of heart disease. But it also stated that, after evaluating current research, there was little evidence to support the idea that everyone should lower their sodium intake to 2,300 mg/day (about a teaspoon). The report went so far as to suggest that too little sodium (1,500 mg/day) could potentially have harmful consequences for some populations, including those with diabetes and heart disease.

The recommendations were in direct contrast with the U.S. Department of Health and Human Services guidelines, which advise adults consume no more than 2,300 mg/day, and that high-risk groups, including people 51 and older and those with high blood pressure and diabetes, reduce their sodium intake to 1,500 mg/day.

The report reignited the salt debate, prompting the American Journal of Hypertension to invite experts on both sides of the sodium aisle to weigh in on the controversy for its October 2013 issue.

The six response papers in the issue offer a wide range of opinions. Some, including those submitted by the Centers for Disease Control and Prevention and the New York City Department of Health, argue that reducing sodium intake saves lives and that efforts to get all Americans to consume less salt should continue.

Others point out that the IOC report said that high levels of sodium were harmful and that this common ground has been lost in the controversy.

Another expert contends that there is no evidence that the current average level of 3,400 mg/day is physiologically damaging.

The commentary comes down to this: Experts are unclear exactly how much sodium is ideal for good health. There is likely a middle ground, but the amount cannot yet be pinpointed.

Massive sodium intake has led to an increase in blood pressure. Yet in one study, more people with low consumption (2,400 mg/day) died than those with high consumption (5,980 mg/day), as Runner's World Sweat Science blogger Alex Hutchinson points out.

His take: Aim for the amount that tastes good. For runners, we’ll add: Know thy sweat rate. Sodium is essential to hydration, and if it's hot and you're training hard, you can lose as much as 3,000 mg during an hour run. Knowing about how much you lose--sweat rate is highly individual and varies from summer to fall to winter--can serve as a guide to how much you need to replace.